TOC Page | 117 Psorothamnus arborescens var. pubescens (Parish) Barneby Marble Canyon Dalea Family: Fabaceae Synonyms: None NESL Status: G4 Federal Status: None Plant Description: Armed shrubs 4-10 dm tall; leaves 1.4-3.8cm long, leaflets 7-15, glandular beneath, strigose on both sides. Racemes 11-21 flowered, 1.8-4.5cm long. Calyx 8-10mm long, the tube 3.8- 4.8mm long, 10-ribbed, villous, the teeth 3.6-5.2mm long, linear-lanceolate, as long as the tube; flowers 8.1-10.6 mm long, indigo; valves of pods with large, round, discrete yellowish or orange blister glands, pubescent between blister glands. Flowering and fruiting from May to June. Similar species: Differs consistently from P. fremontii only in the ornamentation of the pod. P. fremontii has small orange glands that are confluent lengthwise into crowded ridges towards the pod’s beak. P. arborescens has large round blister glands separated from one another by spaces as wide as their diameter. Habitat: On soils derived from the Moenkopi Formation in mixed desert shrub communities between 3400 – 4900ft Distribution: Endemic Northern Coconino County, AZ, in the vicinity of Marble Canyon. Navajo Nation Distribution: Currently only known from Navajo Springs area, south of Navajo Bridge. Potential Navajo Nation Distribution: Lee’s Backbone to Bitter Springs. Recommended Survey Period: Proper identification is only possible during the flowering and fruiting period in May and June. Recommended Avoidance: A 200 ft buffer zone is recommended to avoid disturbance; may be more or less depending on size and nature of the project. References: Arizona Rare Plant Committee. 2001. Arizona rare plant field guide: a collaboration of agencies and organizations. Washington: U.S. Government Printing Office. http://aznps.org/rareplants.html Cronquist, A. et al., eds. 1989. Intermountain Flora, vol. 3, Part B. New York Botanical Garden, Bronx, NY. p. 268. Welsh, S.L., N.D. Atwood, S. Goodrich, L.C. Higgins. 2003. A Utah Flora: Third Edition. Brigham Young University, Provo, UT. Daniela Roth. 2008. Species account for Psorothamnus arborescens var. pubescens. Navajo Natural Heritage Program, P.O. Box 1480, Window Rock, AZ 86515. Additional copies at http://nnhp.nndfw.org/ TOC Page | 118 Psorothamnus arborescens var. pubescens ©Daniela Roth, NNHP Psorothamnus arborescens var. pubescens habitat ©Daniela Roth, NNHP Daniela Roth. 2008. Species account for Psorothamnus arborescens var. pubescens. Navajo Natural Heritage Program, P.O. Box 1480, Window Rock, AZ 86515. Additional copies at http://nnhp.nndfw.org/ .